People travel by aircraft to see the sites or attend events. Travel for Aircraft is about travel for aircraft to see them in their various locations — be they museums, static displays, airfield ramps or languishing in fields.

Lockheed’s M-21/D-21B Tagboard in the Main Gallery of the Museum of Flight − photo by Joseph May

The Museum of Flight has a beautiful pairing of Mach 3+ aircraft created for high value Cold War reconnaissance missions, the Lockheed M-21 as well as D-21 drone — the M-21 (known by Lockheed as “Archangel” and by the USAF as “Oxcart”, now known most often as “Blackbird”) was the mothership to the drone which has the codename Tagboard. The M-21 design is modified from the A-12 (the direct ancestor to the SR-71 ) externally differentiated by a second cockpit, the Launch System Operator’s position — making it difficult indeed to determine if one is looking at an M-21 or an SR-71 unless the D-21 is mounted atop the fuselage. The D-21 Tagboard shares in the Blackbird lineage with its titanium construction and a design to live in the Mach 3+ extremely high altitude regime — not briefly visiting it. Unlike the M-21, it was powered by a ramjet engine (Marquardt XRJ-43) and intended as a one shot vehicle — giving an idea how valuable recce information can be and the costs associated with the Cold War. The M-21, of course, would lift the D-21 to altitude and speed whereupon the D-21′s engine would be started and, with the three M-21/D-21 engines at full power the drone would release and ease upward, between the closely neighboring vertical fines of the M-21, through the mothership’s Mach 3 shockwave. Easy to envision but the aeronautical physics were daunting. After a few successful releases a catastrophic accident occurred during a release in which both aircraft were lost as well as one of the crew. This ended the M-21/D-21 program with a mothership change to a B-52H with modifications to the D-21. All remaining Tagboards were modified to the D-21B design by the addition of dorsal shackles (for mounting to the Stratofortress wing pylons), a 20% increase in the vertical fin area and ventral mounting points to attach a booster rocket (needed to propel the drone to ramjet operational speeds).

A closer view of the rare pairing of the Lockheed M-21/D-21B Tagboard exhibit − photo by Joseph May

Lockheed M-21/D-21B Tagboard − photo by Joseph May

The intelligent end of the M-21/D-21B Tagboard duo − photo by Joseph May

Lockheed M-21 was a two seat version of the A-12 (the 2nd position is for the launch system operator) and made it externally very much alike the SR-71 − photo by Joseph May

The business end of the Lockheed M-21/D-21B Tagboard strategic reconnaissance assembly − photo by Joseph May

The Lockheed M-21/D-21B Tagboard pairing had three high tech engines (all three used JP-7 fuel) for continual operation at Mach 3 and higher − photo by Joseph May

John L. Little (Asst. Curator and Research Team Leader/Museum of Flight) was more than kind to clarify why M-21 has a D-21B mounted atop rather than a D-21 and it is simply that there are no D-21 Tagboards as all existing ones had been modified to the D-21B. Additionally, both aircraft are on loan from the National Museum of the U.S. Air Force. More from Mr. Little in the Wednesday post which emphasizes the D-21B Tagboard.